src/pencil-context.cpp

   1 /** \file
   2  * Pencil event context implementation.
   3  */
   4
   5 /*
   6  * Authors:
   7  *   Lauris Kaplinski <lauris@kaplinski.com>
   8  *   bulia byak <buliabyak@users.sf.net>
   9  *
  10  * Copyright (C) 2000 Lauris Kaplinski
  11  * Copyright (C) 2000-2001 Ximian, Inc.
  12  * Copyright (C) 2002 Lauris Kaplinski
  13  * Copyright (C) 2004 Monash University
  14  *
  15  * Released under GNU GPL, read the file 'COPYING' for more information
  16  */
  17
  18 #include <gdk/gdkkeysyms.h>
  19
  20 #include "pencil-context.h"
  21 #include "desktop.h"
  22 #include "desktop-handles.h"
  23 #include "selection.h"
  24 #include "selection-chemistry.h"
  25 #include "draw-anchor.h"
  26 #include "message-stack.h"
  27 #include "message-context.h"
  28 #include "modifier-fns.h"
  29 #include "sp-path.h"
  30 #include "preferences.h"
  31 #include "snap.h"
  32 #include "pixmaps/cursor-pencil.xpm"
  33 #include <2geom/sbasis-to-bezier.h>
  34 #include <2geom/bezier-utils.h>
  35 #include "display/canvas-bpath.h"
  36 #include <glibmm/i18n.h>
  37 #include "libnr/in-svg-plane.h"
  38 #include "context-fns.h"
  39 #include "sp-namedview.h"
  40 #include "xml/repr.h"
  41 #include "document.h"
  42 #include "desktop-style.h"
  43 #include "macros.h"
  44 #include "display/curve.h"
  45
  46 static void sp_pencil_context_class_init(SPPencilContextClass *klass);
  47 static void sp_pencil_context_init(SPPencilContext *pc);
  48 static void sp_pencil_context_setup(SPEventContext *ec);
  49 static void sp_pencil_context_dispose(GObject *object);
  50
  51 static gint sp_pencil_context_root_handler(SPEventContext *event_context, GdkEvent *event);
  52 static gint pencil_handle_button_press(SPPencilContext *const pc, GdkEventButton const &bevent);
  53 static gint pencil_handle_motion_notify(SPPencilContext *const pc, GdkEventMotion const &mevent);
  54 static gint pencil_handle_button_release(SPPencilContext *const pc, GdkEventButton const &revent);
  55 static gint pencil_handle_key_press(SPPencilContext *const pc, guint const keyval, guint const state);
  56 static gint pencil_handle_key_release(SPPencilContext *const pc, guint const keyval, guint const state);
  57
  58 static void spdc_set_startpoint(SPPencilContext *pc, Geom::Point const p);
  59 static void spdc_set_endpoint(SPPencilContext *pc, Geom::Point const p);
  60 static void spdc_finish_endpoint(SPPencilContext *pc);
  61 static void spdc_add_freehand_point(SPPencilContext *pc, Geom::Point p, guint state);
  62 static void fit_and_split(SPPencilContext *pc);
  63 static void interpolate(SPPencilContext *pc);
  64 static void sketch_interpolate(SPPencilContext *pc);
  65
  66 static SPDrawContextClass *pencil_parent_class;
  67 static Geom::Point pencil_drag_origin_w(0, 0);
  68 static bool pencil_within_tolerance = false;
  69
  70 /**
  71  * Register SPPencilContext class with Gdk and return its type number.
  72  */
  73 GType
  74 sp_pencil_context_get_type()
  75 {
  76     static GType type = 0;
  77     if (!type) {
  78         GTypeInfo info = {
  79             sizeof(SPPencilContextClass),
  80             NULL, NULL,
  81             (GClassInitFunc) sp_pencil_context_class_init,
  82             NULL, NULL,
  83             sizeof(SPPencilContext),
  84             4,
  85             (GInstanceInitFunc) sp_pencil_context_init,
  86             NULL,   /* value_table */
  87         };
  88         type = g_type_register_static(SP_TYPE_DRAW_CONTEXT, "SPPencilContext", &info, (GTypeFlags)0);
  89     }
  90     return type;
  91 }
  92
  93 /**
  94  * Initialize SPPencilContext vtable.
  95  */
  96 static void
  97 sp_pencil_context_class_init(SPPencilContextClass *klass)
  98 {
  99     GObjectClass *object_class;
 100     SPEventContextClass *event_context_class;
 101
 102     object_class = (GObjectClass *) klass;
 103     event_context_class = (SPEventContextClass *) klass;
 104
 105     pencil_parent_class = (SPDrawContextClass*)g_type_class_peek_parent(klass);
 106
 107     object_class->dispose = sp_pencil_context_dispose;
 108
 109     event_context_class->setup = sp_pencil_context_setup;
 110     event_context_class->root_handler = sp_pencil_context_root_handler;
 111 }
 112
 113 /**
 114  * Callback to initialize SPPencilContext object.
 115  */
 116 static void
 117 sp_pencil_context_init(SPPencilContext *pc)
 118 {
 119     SPEventContext *event_context = SP_EVENT_CONTEXT(pc);
 120
 121     event_context->cursor_shape = cursor_pencil_xpm;
 122     event_context->hot_x = 4;
 123     event_context->hot_y = 4;
 124
 125     pc->npoints = 0;
 126     pc->state = SP_PENCIL_CONTEXT_IDLE;
 127     pc->req_tangent = Geom::Point(0, 0);
 128
 129     // since SPPencilContext is not properly constructed...
 130     pc->sketch_interpolation = Geom::Piecewise<Geom::D2<Geom::SBasis> >();
 131     pc->sketch_n = 0;
 132 }
 133
 134 /**
 135  * Callback to setup SPPencilContext object.
 136  */
 137 static void
 138 sp_pencil_context_setup(SPEventContext *ec)
 139 {
 140     Inkscape::Preferences *prefs = Inkscape::Preferences::get();
 141     if (prefs->getBool("/tools/freehand/pencil/selcue")) {
 142         ec->enableSelectionCue();
 143     }
 144
 145     if (((SPEventContextClass *) pencil_parent_class)->setup) {
 146         ((SPEventContextClass *) pencil_parent_class)->setup(ec);
 147     }
 148
 149     SPPencilContext *const pc = SP_PENCIL_CONTEXT(ec);
 150     pc->is_drawing = false;
 151
 152     pc->anchor_statusbar = false;
 153 }
 154
 155 static void
 156 sp_pencil_context_dispose(GObject *object)
 157 {
 158     G_OBJECT_CLASS(pencil_parent_class)->dispose(object);
 159 }
 160
 161 /** Snaps new node relative to the previous node. */
 162 static void
 163 spdc_endpoint_snap(SPPencilContext const *pc, Geom::Point &p, guint const state)
 164 {
 165     if ((state & GDK_CONTROL_MASK)) { //CTRL enables constrained snapping
 166         spdc_endpoint_snap_rotation(pc, p, pc->p[0], state);
 167     } else {
 168         if (!(state & GDK_SHIFT_MASK)) { //SHIFT disables all snapping, except the angular snapping above
 169                                          //After all, the user explicitely asked for angular snapping by
 170                                          //pressing CTRL
 171             spdc_endpoint_snap_free(pc, p, state);
 172         }
 173     }
 174 }
 175
 176 /**
 177  * Callback for handling all pencil context events.
 178  */
 179 gint
 180 sp_pencil_context_root_handler(SPEventContext *const ec, GdkEvent *event)
 181 {
 182     SPPencilContext *const pc = SP_PENCIL_CONTEXT(ec);
 183
 184     gint ret = FALSE;
 185
 186     switch (event->type) {
 187         case GDK_BUTTON_PRESS:
 188             ret = pencil_handle_button_press(pc, event->button);
 189             break;
 190
 191         case GDK_MOTION_NOTIFY:
 192             ret = pencil_handle_motion_notify(pc, event->motion);
 193             break;
 194
 195         case GDK_BUTTON_RELEASE:
 196             ret = pencil_handle_button_release(pc, event->button);
 197             break;
 198
 199         case GDK_KEY_PRESS:
 200             ret = pencil_handle_key_press(pc, get_group0_keyval (&event->key), event->key.state);
 201             break;
 202
 203         case GDK_KEY_RELEASE:
 204             ret = pencil_handle_key_release(pc, get_group0_keyval (&event->key), event->key.state);
 205             break;
 206
 207         default:
 208             break;
 209     }
 210
 211     if (!ret) {
 212         gint (*const parent_root_handler)(SPEventContext *, GdkEvent *)
 213             = ((SPEventContextClass *) pencil_parent_class)->root_handler;
 214         if (parent_root_handler) {
 215             ret = parent_root_handler(ec, event);
 216         }
 217     }
 218
 219     return ret;
 220 }
 221
 222 static gint
 223 pencil_handle_button_press(SPPencilContext *const pc, GdkEventButton const &bevent)
 224 {
 225     gint ret = FALSE;
 226     SPEventContext *event_context = SP_EVENT_CONTEXT(pc);
 227     if ( bevent.button == 1  && !event_context->space_panning) {
 228
 229         SPDrawContext *dc = SP_DRAW_CONTEXT (pc);
 230         SPDesktop *desktop = SP_EVENT_CONTEXT_DESKTOP(dc);
 231         Inkscape::Selection *selection = sp_desktop_selection(desktop);
 232
 233         if (Inkscape::have_viable_layer(desktop, dc->_message_context) == false) {
 234             return TRUE;
 235         }
 236
 237         Geom::Point const button_w(bevent.x, bevent.y);
 238
 239         /* Find desktop coordinates */
 240         Geom::Point p = pc->desktop->w2d(button_w);
 241
 242         /* Test whether we hit any anchor. */
 243         SPDrawAnchor *anchor = spdc_test_inside(pc, button_w);
 244
 245         pencil_drag_origin_w = Geom::Point(bevent.x,bevent.y);
 246         pencil_within_tolerance = true;
 247
 248         switch (pc->state) {
 249             case SP_PENCIL_CONTEXT_ADDLINE:
 250                 /* Current segment will be finished with release */
 251                 ret = TRUE;
 252                 break;
 253             default:
 254                 /* Set first point of sequence */
 255                 if (bevent.state & GDK_CONTROL_MASK) {
 256                     spdc_create_single_dot(event_context, from_2geom(p), "/tools/freehand/pencil", bevent.state);
 257                     ret = true;
 258                     break;
 259                 }
 260                 if (anchor) {
 261                     p = to_2geom(anchor->dp);
 262                     desktop->messageStack()->flash(Inkscape::NORMAL_MESSAGE, _("Continuing selected path"));
 263                 } else {
 264
 265                     if (!(bevent.state & GDK_SHIFT_MASK)) {
 266
 267                         // This is the first click of a new curve; deselect item so that
 268                         // this curve is not combined with it (unless it is drawn from its
 269                         // anchor, which is handled by the sibling branch above)
 270                         selection->clear();
 271                         desktop->messageStack()->flash(Inkscape::NORMAL_MESSAGE, _("Creating new path"));
 272                         SnapManager &m = desktop->namedview->snap_manager;
 273                         m.setup(desktop);
 274                         Inkscape::SnappedPoint const s = m.freeSnap(Inkscape::SnapPreferences::SNAPPOINT_NODE, p);
 275                         if (s.getSnapped()) {
 276                                 s.getPoint(p);
 277                                 pc->prev_snap_was_succesful = true;
 278                         } else {
 279                                 pc->prev_snap_was_succesful = false;
 280                         }
 281                     } else if (selection->singleItem() && SP_IS_PATH(selection->singleItem())) {
 282                         desktop->messageStack()->flash(Inkscape::NORMAL_MESSAGE, _("Appending to selected path"));
 283                     }
 284                 }
 285                 pc->sa = anchor;
 286                 spdc_set_startpoint(pc, from_2geom(p));
 287                 ret = TRUE;
 288                 break;
 289         }
 290
 291         pc->is_drawing = true;
 292     }
 293     return ret;
 294 }
 295
 296 static gint
 297 pencil_handle_motion_notify(SPPencilContext *const pc, GdkEventMotion const &mevent)
 298 {
 299     if ((mevent.state & GDK_CONTROL_MASK) && (mevent.state & GDK_BUTTON1_MASK)) {
 300         // mouse was accidentally moved during Ctrl+click;
 301         // ignore the motion and create a single point
 302         pc->is_drawing = false;
 303         return TRUE;
 304     }
 305     gint ret = FALSE;
 306     SPDesktop *const dt = pc->desktop;
 307
 308     SPEventContext *event_context = SP_EVENT_CONTEXT(pc);
 309     if (event_context->space_panning || mevent.state & GDK_BUTTON2_MASK || mevent.state & GDK_BUTTON3_MASK) {
 310         // allow scrolling
 311         return FALSE;
 312     }
 313
 314     if ( ( mevent.state & GDK_BUTTON1_MASK ) && !pc->grab && pc->is_drawing) {
 315         /* Grab mouse, so release will not pass unnoticed */
 316         pc->grab = SP_CANVAS_ITEM(dt->acetate);
 317         sp_canvas_item_grab(pc->grab, ( GDK_KEY_PRESS_MASK | GDK_BUTTON_PRESS_MASK   |
 318                                         GDK_BUTTON_RELEASE_MASK |
 319                                         GDK_POINTER_MOTION_MASK  ),
 320                             NULL, mevent.time);
 321     }
 322
 323     /* Find desktop coordinates */
 324     Geom::Point p = to_2geom(dt->w2d(Geom::Point(mevent.x, mevent.y)));
 325
 326     /* Test whether we hit any anchor. */
 327     SPDrawAnchor *anchor = spdc_test_inside(pc, Geom::Point(mevent.x, mevent.y));
 328
 329     if (pencil_within_tolerance) {
 330         Inkscape::Preferences *prefs = Inkscape::Preferences::get();
 331         gint const tolerance = prefs->getIntLimited("/options/dragtolerance/value", 0, 0, 100);
 332         if ( Geom::LInfty( Geom::Point(mevent.x,mevent.y) - pencil_drag_origin_w ) < tolerance ) {
 333             return FALSE;   // Do not drag if we're within tolerance from origin.
 334         }
 335     }
 336
 337     // Once the user has moved farther than tolerance from the original location
 338     // (indicating they intend to move the object, not click), then always process the
 339     // motion notify coordinates as given (no snapping back to origin)
 340     pencil_within_tolerance = false;
 341
 342     switch (pc->state) {
 343         case SP_PENCIL_CONTEXT_ADDLINE:
 344             /* Set red endpoint */
 345             if (anchor) {
 346                 p = to_2geom(anchor->dp);
 347             } else {
 348                 Geom::Point ptnr = from_2geom(p);
 349                 spdc_endpoint_snap(pc, ptnr, mevent.state);
 350                 p = to_2geom(ptnr);
 351             }
 352             spdc_set_endpoint(pc, from_2geom(p));
 353             ret = TRUE;
 354             break;
 355         default:
 356             /* We may be idle or already freehand */
 357             if ( mevent.state & GDK_BUTTON1_MASK && pc->is_drawing ) {
 358                 pc->state = SP_PENCIL_CONTEXT_FREEHAND;
 359                 if ( !pc->sa && !pc->green_anchor ) {
 360                     /* Create green anchor */
 361                     pc->green_anchor = sp_draw_anchor_new(pc, pc->green_curve, TRUE, pc->p[0]);
 362                 }
 363                 /** \todo
 364                  * fixme: I am not sure whether we want to snap to anchors
 365                  * in middle of freehand (Lauris)
 366                  */
 367                 SnapManager &m = dt->namedview->snap_manager;
 368
 369                 if (anchor) {
 370                     p = to_2geom(anchor->dp);
 371                 } else if ((mevent.state & GDK_SHIFT_MASK) == 0) {
 372                     m.setup(dt);
 373                     Inkscape::SnappedPoint const s = m.freeSnap(Inkscape::SnapPreferences::SNAPPOINT_NODE, p);
 374                     if (s.getSnapped()) {
 375                         s.getPoint(p);
 376                         pc->prev_snap_was_succesful = true;
 377                     } else {
 378                         pc->prev_snap_was_succesful = false;
 379                     }
 380                 }
 381                 if ( pc->npoints != 0) { // buttonpress may have happened before we entered draw context!
 382                         if (!(pc->prev_snap_was_succesful && m.snapprefs.getSnapPostponedGlobally())) {
 383                             // When snapping is enabled but temporarily on hold because the mouse is moving
 384                                 // fast, then we don't want to add nodes off-grid
 385                                 spdc_add_freehand_point(pc, from_2geom(p), mevent.state);
 386                             ret = TRUE;
 387                         }
 388                 }
 389
 390                 if (anchor && !pc->anchor_statusbar) {
 391                     pc->_message_context->set(Inkscape::NORMAL_MESSAGE, _("<b>Release</b> here to close and finish the path."));
 392                     pc->anchor_statusbar = true;
 393                 } else if (!anchor && pc->anchor_statusbar) {
 394                     pc->_message_context->clear();
 395                     pc->anchor_statusbar = false;
 396                 } else if (!anchor) {
 397                     pc->_message_context->set(Inkscape::NORMAL_MESSAGE, _("Drawing a freehand path"));
 398                 }
 399
 400             } else {
 401                 if (anchor && !pc->anchor_statusbar) {
 402                     pc->_message_context->set(Inkscape::NORMAL_MESSAGE, _("<b>Drag</b> to continue the path from this point."));
 403                     pc->anchor_statusbar = true;
 404                 } else if (!anchor && pc->anchor_statusbar) {
 405                     pc->_message_context->clear();
 406                     pc->anchor_statusbar = false;
 407                 }
 408             }
 409             break;
 410     }
 411     return ret;
 412 }
 413
 414 static gint
 415 pencil_handle_button_release(SPPencilContext *const pc, GdkEventButton const &revent)
 416 {
 417     gint ret = FALSE;
 418
 419     SPEventContext *event_context = SP_EVENT_CONTEXT(pc);
 420     if ( revent.button == 1 && pc->is_drawing && !event_context->space_panning) {
 421         SPDesktop *const dt = pc->desktop;
 422
 423         pc->is_drawing = false;
 424
 425         /* Find desktop coordinates */
 426         Geom::Point p = dt->w2d(Geom::Point(revent.x, revent.y));
 427
 428         /* Test whether we hit any anchor. */
 429         SPDrawAnchor *anchor = spdc_test_inside(pc, Geom::Point(revent.x,
 430                                                               revent.y));
 431
 432         switch (pc->state) {
 433             case SP_PENCIL_CONTEXT_IDLE:
 434                 /* Releasing button in idle mode means single click */
 435                 /* We have already set up start point/anchor in button_press */
 436                 if (!(revent.state & GDK_CONTROL_MASK)) {
 437                     // Ctrl+click creates a single point so only set context in ADDLINE mode when Ctrl isn't pressed
 438                     pc->state = SP_PENCIL_CONTEXT_ADDLINE;
 439                 }
 440                 ret = TRUE;
 441                 break;
 442             case SP_PENCIL_CONTEXT_ADDLINE:
 443                 /* Finish segment now */
 444                 if (anchor) {
 445                     p = anchor->dp;
 446                 } else {
 447                     spdc_endpoint_snap(pc, p, revent.state);
 448                 }
 449                 pc->ea = anchor;
 450                 spdc_set_endpoint(pc, p);
 451                 spdc_finish_endpoint(pc);
 452                 pc->state = SP_PENCIL_CONTEXT_IDLE;
 453                 ret = TRUE;
 454                 break;
 455             case SP_PENCIL_CONTEXT_FREEHAND:
 456                 if (revent.state & GDK_MOD1_MASK) {
 457                     /* sketch mode: interpolate the sketched path and improve the current output path with the new interpolation. don't finish sketch */
 458                     if (anchor) {
 459                         p = anchor->dp;
 460                     }
 461                     pc->ea = anchor;
 462
 463                     dt->messageStack()->flash(Inkscape::NORMAL_MESSAGE, _("Sketching: release <b>Alt</b> to finalize current curve"));
 464
 465                     sketch_interpolate(pc);
 466
 467                     pc->state = SP_PENCIL_CONTEXT_SKETCH;
 468                 } else {
 469                     /* Finish segment now */
 470                     /// \todo fixme: Clean up what follows (Lauris)
 471                     if (anchor) {
 472                         p = anchor->dp;
 473                     }
 474                     pc->ea = anchor;
 475                     /* Write curves to object */
 476
 477                     dt->messageStack()->flash(Inkscape::NORMAL_MESSAGE, _("Finishing freehand"));
 478
 479                     interpolate(pc);
 480                     spdc_concat_colors_and_flush(pc, FALSE);
 481                     pc->sa = NULL;
 482                     pc->ea = NULL;
 483                     if (pc->green_anchor) {
 484                         pc->green_anchor = sp_draw_anchor_destroy(pc->green_anchor);
 485                     }
 486                     pc->state = SP_PENCIL_CONTEXT_IDLE;
 487                 }
 488                 ret = TRUE;
 489                 break;
 490             case SP_PENCIL_CONTEXT_SKETCH:
 491             default:
 492                 break;
 493         }
 494
 495         if (pc->grab) {
 496             /* Release grab now */
 497             sp_canvas_item_ungrab(pc->grab, revent.time);
 498             pc->grab = NULL;
 499         }
 500
 501         ret = TRUE;
 502     }
 503     return ret;
 504 }
 505
 506 static void
 507 pencil_cancel (SPPencilContext *const pc)
 508 {
 509     if (pc->grab) {
 510         /* Release grab now */
 511         sp_canvas_item_ungrab(pc->grab, 0);
 512         pc->grab = NULL;
 513     }
 514
 515     pc->is_drawing = false;
 516
 517     pc->state = SP_PENCIL_CONTEXT_IDLE;
 518
 519     pc->red_curve->reset();
 520     sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(pc->red_bpath), NULL);
 521     while (pc->green_bpaths) {
 522         gtk_object_destroy(GTK_OBJECT(pc->green_bpaths->data));
 523         pc->green_bpaths = g_slist_remove(pc->green_bpaths, pc->green_bpaths->data);
 524     }
 525     pc->green_curve->reset();
 526     if (pc->green_anchor) {
 527         pc->green_anchor = sp_draw_anchor_destroy(pc->green_anchor);
 528     }
 529
 530     pc->_message_context->clear();
 531     pc->_message_context->flash(Inkscape::NORMAL_MESSAGE, _("Drawing cancelled"));
 532
 533     sp_canvas_end_forced_full_redraws(pc->desktop->canvas);
 534 }
 535
 536 static gint
 537 pencil_handle_key_press(SPPencilContext *const pc, guint const keyval, guint const state)
 538 {
 539     gint ret = FALSE;
 540     switch (keyval) {
 541         case GDK_Up:
 542         case GDK_Down:
 543         case GDK_KP_Up:
 544         case GDK_KP_Down:
 545             // Prevent the zoom field from activation.
 546             if (!mod_ctrl_only(state)) {
 547                 ret = TRUE;
 548             }
 549             break;
 550         case GDK_Escape:
 551             if (pc->npoints != 0) {
 552                 // if drawing, cancel, otherwise pass it up for deselecting
 553                 if (pc->state != SP_PENCIL_CONTEXT_IDLE) {
 554                     pencil_cancel (pc);
 555                     ret = TRUE;
 556                 }
 557             }
 558             break;
 559         case GDK_z:
 560         case GDK_Z:
 561             if (mod_ctrl_only(state) && pc->npoints != 0) {
 562                 // if drawing, cancel, otherwise pass it up for undo
 563                 if (pc->state != SP_PENCIL_CONTEXT_IDLE) {
 564                     pencil_cancel (pc);
 565                     ret = TRUE;
 566                 }
 567             }
 568             break;
 569         case GDK_g:
 570         case GDK_G:
 571             if (mod_shift_only(state)) {
 572                 sp_selection_to_guides(SP_EVENT_CONTEXT(pc)->desktop);
 573                 ret = true;
 574             }
 575             break;
 576         default:
 577             break;
 578     }
 579     return ret;
 580 }
 581
 582 static gint
 583 pencil_handle_key_release(SPPencilContext *const pc, guint const keyval, guint const /*state*/)
 584 {
 585     gint ret = FALSE;
 586     switch (keyval) {
 587         case GDK_Alt_L:
 588         case GDK_Alt_R:
 589         case GDK_Meta_L:
 590         case GDK_Meta_R:
 591             if (pc->state == SP_PENCIL_CONTEXT_SKETCH) {
 592                 spdc_concat_colors_and_flush(pc, FALSE);
 593                 pc->sketch_n = 0;
 594                 pc->sa = NULL;
 595                 pc->ea = NULL;
 596                 if (pc->green_anchor) {
 597                     pc->green_anchor = sp_draw_anchor_destroy(pc->green_anchor);
 598                 }
 599                 pc->state = SP_PENCIL_CONTEXT_IDLE;
 600                 ret = TRUE;
 601             }
 602             break;
 603         default:
 604             break;
 605     }
 606     return ret;
 607 }
 608
 609 /**
 610  * Reset points and set new starting point.
 611  */
 612 static void
 613 spdc_set_startpoint(SPPencilContext *const pc, Geom::Point const p)
 614 {
 615     pc->npoints = 0;
 616     pc->red_curve_is_valid = false;
 617     if (in_svg_plane(p)) {
 618         pc->p[pc->npoints++] = p;
 619     }
 620 }
 621
 622 /**
 623  * Change moving endpoint position.
 624  * <ul>
 625  * <li>Ctrl constrains to moving to H/V direction, snapping in given direction.
 626  * <li>Otherwise we snap freely to whatever attractors are available.
 627  * </ul>
 628  *
 629  * Number of points is (re)set to 2 always, 2nd point is modified.
 630  * We change RED curve.
 631  */
 632 static void
 633 spdc_set_endpoint(SPPencilContext *const pc, Geom::Point const p)
 634 {
 635     if (pc->npoints == 0) {
 636         return;
 637         /* May occur if first point wasn't in SVG plane (e.g. weird w2d transform, perhaps from bad
 638          * zoom setting).
 639          */
 640     }
 641     g_return_if_fail( pc->npoints > 0 );
 642
 643     pc->red_curve->reset();
 644     if ( ( p == pc->p[0] )
 645          || !in_svg_plane(p) )
 646     {
 647         pc->npoints = 1;
 648     } else {
 649         pc->p[1] = p;
 650         pc->npoints = 2;
 651
 652         pc->red_curve->moveto(pc->p[0]);
 653         pc->red_curve->lineto(pc->p[1]);
 654         pc->red_curve_is_valid = true;
 655
 656         sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(pc->red_bpath), pc->red_curve);
 657     }
 658 }
 659
 660 /**
 661  * Finalize addline.
 662  *
 663  * \todo
 664  * fixme: I'd like remove red reset from concat colors (lauris).
 665  * Still not sure, how it will make most sense.
 666  */
 667 static void
 668 spdc_finish_endpoint(SPPencilContext *const pc)
 669 {
 670     if ( ( pc->red_curve->is_empty() )
 671          || ( *(pc->red_curve->first_point()) == *(pc->red_curve->second_point())   ) )
 672     {
 673         pc->red_curve->reset();
 674         sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(pc->red_bpath), NULL);
 675     } else {
 676         /* Write curves to object. */
 677         spdc_concat_colors_and_flush(pc, FALSE);
 678         pc->sa = NULL;
 679         pc->ea = NULL;
 680     }
 681 }
 682
 683
 684 static void
 685 spdc_add_freehand_point(SPPencilContext *pc, Geom::Point p, guint /*state*/)
 686 {
 687     g_assert( pc->npoints > 0 );
 688     g_return_if_fail(unsigned(pc->npoints) < G_N_ELEMENTS(pc->p));
 689
 690     if ( ( p != pc->p[ pc->npoints - 1 ] )
 691          && in_svg_plane(p) )
 692     {
 693         pc->ps.push_back(p);
 694         pc->p[pc->npoints++] = p;
 695         fit_and_split(pc);
 696     }
 697 }
 698
 699 static inline double
 700 square(double const x)
 701 {
 702     return x * x;
 703 }
 704
 705 static void
 706 interpolate(SPPencilContext *pc)
 707 {
 708
 709     g_assert( pc->ps.size() > 1 );
 710
 711     Inkscape::Preferences *prefs = Inkscape::Preferences::get();
 712     double const tol = prefs->getDoubleLimited("/tools/freehand/pencil/tolerance", 10.0, 1.0, 100.0) * 0.4;
 713     double const tolerance_sq = 0.02 * square( pc->desktop->w2d().descrim() *
 714                                                tol) * exp(0.2*tol - 2);
 715
 716     g_assert(is_zero(pc->req_tangent)
 717              || is_unit_vector(pc->req_tangent));
 718     Geom::Point const tHatEnd(0, 0);
 719
 720     guint n_points  = pc->ps.size();
 721     pc->green_curve->reset();
 722     pc->red_curve->reset();
 723     pc->red_curve_is_valid = false;
 724
 725     Geom::Point * b = g_new(Geom::Point, 4*n_points);
 726     Geom::Point * points = g_new(Geom::Point, 4*n_points);
 727     for (unsigned int i = 0; i < pc->ps.size(); i++) {
 728         points[i] = pc->ps[i];
 729     }
 730
 731     // worst case gives us a segment per point
 732     int max_segs = 4*n_points;
 733
 734     int const n_segs = Geom::bezier_fit_cubic_r(b, points, n_points,
 735                                              tolerance_sq, max_segs);
 736
 737     if ( n_segs > 0)
 738     {
 739         /* Fit and draw and reset state */
 740         pc->green_curve->moveto(b[0]);
 741         for (int c = 0; c < n_segs; c++) {
 742             pc->green_curve->curveto(b[4*c+1], b[4*c+2], b[4*c+3]);
 743         }
 744         sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(pc->red_bpath), pc->green_curve);
 745
 746         /* Fit and draw and copy last point */
 747         g_assert(!pc->green_curve->is_empty());
 748
 749         /* Set up direction of next curve. */
 750         {
 751             Geom::CubicBezier const * last_seg = dynamic_cast<Geom::CubicBezier const *>(pc->green_curve->last_segment());
 752             g_assert( last_seg );      // Relevance: validity of (*last_seg)[2]
 753             pc->p[0] = last_seg->finalPoint();
 754             pc->npoints = 1;
 755             Geom::Point const req_vec( pc->p[0] - (*last_seg)[2] );
 756             pc->req_tangent = ( ( Geom::is_zero(req_vec) || !in_svg_plane(req_vec) )
 757                                 ? Geom::Point(0, 0)
 758                                 : Geom::unit_vector(req_vec) );
 759         }
 760     }
 761     g_free(b);
 762     g_free(points);
 763     pc->ps.clear();
 764 }
 765
 766
 767 /* interpolates the sketched curve and tweaks the current sketch interpolation*/
 768 static void
 769 sketch_interpolate(SPPencilContext *pc)
 770 {
 771     g_assert( pc->ps.size() > 1 );
 772
 773     Inkscape::Preferences *prefs = Inkscape::Preferences::get();
 774     double const tol = prefs->getDoubleLimited("/tools/freehand/pencil/tolerance", 10.0, 1.0, 100.0) * 0.4;
 775     double const tolerance_sq = 0.02 * square( pc->desktop->w2d().descrim() *
 776                                                tol) * exp(0.2*tol - 2);
 777
 778     bool average_all_sketches = prefs->getBool("/tools/freehand/pencil/average_all_sketches", true);
 779
 780     g_assert(is_zero(pc->req_tangent)
 781              || is_unit_vector(pc->req_tangent));
 782     Geom::Point const tHatEnd(0, 0);
 783
 784     guint n_points  = pc->ps.size();
 785     pc->red_curve->reset();
 786     pc->red_curve_is_valid = false;
 787
 788     Geom::Point * b = g_new(Geom::Point, 4*n_points);
 789     Geom::Point * points = g_new(Geom::Point, 4*n_points);
 790     for (unsigned i = 0; i < pc->ps.size(); i++) {
 791         points[i] = pc->ps[i];
 792     }
 793
 794     // worst case gives us a segment per point
 795     int max_segs = 4*n_points;
 796
 797     int const n_segs = Geom::bezier_fit_cubic_r(b, points, n_points,
 798                                              tolerance_sq, max_segs);
 799
 800     if ( n_segs > 0)
 801     {
 802         Geom::Path fit(b[0]);
 803         for (int c = 0; c < n_segs; c++) {
 804             fit.appendNew<Geom::CubicBezier>(b[4*c+1], b[4*c+2], b[4*c+3]);
 805         }
 806         Geom::Piecewise<Geom::D2<Geom::SBasis> > fit_pwd2 = fit.toPwSb();
 807
 808         double t =0.;
 809         if ( pc->sketch_n > 0 ) {
 810             if (average_all_sketches) {
 811                 // Average = (sum of all) / n
 812                 //         = (sum of all + new one) / n+1
 813                 //         = ((old average)*n + new one) / n+1
 814                 t = pc->sketch_n / (pc->sketch_n + 1.);
 815             } else {
 816                 t = 0.5;
 817             }
 818         }
 819         pc->sketch_interpolation = Geom::lerp(fit_pwd2, pc->sketch_interpolation, t);
 820         pc->sketch_n++;
 821
 822         pc->green_curve->reset();
 823         pc->green_curve->set_pathvector(Geom::path_from_piecewise(pc->sketch_interpolation, 0.01));
 824         sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(pc->red_bpath), pc->green_curve);
 825
 826         /* Fit and draw and copy last point */
 827         g_assert(!pc->green_curve->is_empty());
 828
 829         /* Set up direction of next curve. */
 830         {
 831             Geom::CubicBezier const * last_seg = dynamic_cast<Geom::CubicBezier const *>(pc->green_curve->last_segment());
 832             g_assert( last_seg );      // Relevance: validity of (*last_seg)[2]
 833             pc->p[0] = last_seg->finalPoint();
 834             pc->npoints = 1;
 835             Geom::Point const req_vec( pc->p[0] - (*last_seg)[2] );
 836             pc->req_tangent = ( ( Geom::is_zero(req_vec) || !in_svg_plane(req_vec) )
 837                                 ? Geom::Point(0, 0)
 838                                 : Geom::unit_vector(req_vec) );
 839         }
 840     }
 841     g_free(b);
 842     g_free(points);
 843     pc->ps.clear();
 844 }
 845
 846 static void
 847 fit_and_split(SPPencilContext *pc)
 848 {
 849     g_assert( pc->npoints > 1 );
 850
 851     double const tolerance_sq = 0;
 852
 853     Geom::Point b[4];
 854     g_assert(is_zero(pc->req_tangent)
 855              || is_unit_vector(pc->req_tangent));
 856     Geom::Point const tHatEnd(0, 0);
 857     int const n_segs = Geom::bezier_fit_cubic_full(b, NULL, pc->p, pc->npoints,
 858                                                 pc->req_tangent, tHatEnd,
 859                                                 tolerance_sq, 1);
 860     if ( n_segs > 0
 861          && unsigned(pc->npoints) < G_N_ELEMENTS(pc->p) )
 862     {
 863         /* Fit and draw and reset state */
 864         pc->red_curve->reset();
 865         pc->red_curve->moveto(b[0]);
 866         pc->red_curve->curveto(b[1], b[2], b[3]);
 867         sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(pc->red_bpath), pc->red_curve);
 868         pc->red_curve_is_valid = true;
 869     } else {
 870         /* Fit and draw and copy last point */
 871
 872         g_assert(!pc->red_curve->is_empty());
 873
 874         /* Set up direction of next curve. */
 875         {
 876             Geom::CubicBezier const * last_seg = dynamic_cast<Geom::CubicBezier const *>(pc->red_curve->last_segment());
 877             g_assert( last_seg );      // Relevance: validity of (*last_seg)[2]
 878             pc->p[0] = last_seg->finalPoint();
 879             pc->npoints = 1;
 880             Geom::Point const req_vec( pc->p[0] - (*last_seg)[2] );
 881             pc->req_tangent = ( ( Geom::is_zero(req_vec) || !in_svg_plane(req_vec) )
 882                                 ? Geom::Point(0, 0)
 883                                 : Geom::unit_vector(req_vec) );
 884         }
 885
 886         pc->green_curve->append_continuous(pc->red_curve, 0.0625);
 887         SPCurve *curve = pc->red_curve->copy();
 888
 889         /// \todo fixme:
 890         SPCanvasItem *cshape = sp_canvas_bpath_new(sp_desktop_sketch(pc->desktop), curve);
 891         curve->unref();
 892         sp_canvas_bpath_set_stroke(SP_CANVAS_BPATH(cshape), pc->green_color, 1.0, SP_STROKE_LINEJOIN_MITER, SP_STROKE_LINECAP_BUTT);
 893
 894         pc->green_bpaths = g_slist_prepend(pc->green_bpaths, cshape);
 895
 896         pc->red_curve_is_valid = false;
 897     }
 898 }
 899
 900
 901 /*
 902   Local Variables:
 903   mode:c++
 904   c-file-style:"stroustrup"
 905   c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
 906   indent-tabs-mode:nil
 907   fill-column:99
 908   End:
 909 */
 910 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99 :